/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: wwy
 * Date: 2024-05-01
 * Time: 14:25
 */
public class FenShuDeZhi{
    public static void main(String[] args) {
     double sum=0;
     int flag=1;
        for (int i = 1; i <=100 ; i++) {
            sum+=flag*(1.0/i);
            flag=-flag;
        }
        System.out.println(sum);
    }
}
